To enable the secondary chemical current sources with an aqueous electrolyte to be sealed, a catalyst is added that speeds up recombination of hydrogen and oxygen evolved on the electrodes of these current sources, as they are charged.
Know in the art is a sealed-in lead-acid electric battery (GB, A, 1471307) comprising a stack of electrodes, a separator, an aqueous electrolyte, and a catalyst. The catalyst is formed by a number of spherical bodies composed of a mixture of carbon, platinum or palladium, and fluoroethylene polymer, which are freely floating on the electrolyte surface in the below-cover space of the battery. When the hydrogen and oxygen generated in the process of charging the battery contact the catalyst bodies, they are recombined to form water which is returned to the electrolyte.
The disadvantage of the above battery resides in that the spherical bodies of the catalyst, while allowing utilization of the gases evolved, cause the weight-specific electrical characteristics of the battery to degrade, since the material of the bodies is not an active substance of the battery.
Also known in the art is a sealed-in battery (JP, B, 54-24096) comprising positive and negative electrodes, separator matrices located between the oppositely poled electrodes, an aqueous electrolyte of silicon oxysulphide in gel form, and a hydrogen/oxygen recombination catalyst. The catalyst is formed by a plate made of a metal of platinum group, disposed in the gas space of the battery and electrically connected to the negative electrodes. To reduce the hydrogen evolution in the process of charging the battery and to absorb the oxygen evolved on the positive electrodes, the negative electrodes contain an excess of active material, i.e. their mass exceeds that required for the normal discharge of the battery by 40%.
Similarly to the first-mentioned design, this battery includes an extra element, i.e. the catalyst plate that is not involved in the basic cell reaction. This results in a complicated battery construction and in degradation of its specific electrical characteristics compared to open-type batteries.